Recent years have seen active development of displays, called see-through displays (or transparent displays), which can not only display images but also allow objects behind the displays to be viewed through screens. To realize such a see-through display, there have been proposed various approaches which use a liquid crystal panel or an organic EL (electroluminescent) panel. For example, Patent Document 1 describes a display 210 functioning as a see-through display, which is configured such that first and second reflective polarizing plates 40 and 270 are disposed on front and back sides, respectively, relative to a light guide 220, which is positioned therebetween, as shown in FIG. 15. Both the first and second reflective polarizing plates 40 and 270 are polarizing plates which reflect a polarization component of a specific polarization and transmit therethrough a polarization component of a polarization perpendicular to specific polarization. Moreover, the light guide 220 has light source 10 attached at an edge. Further, first and second absorptive polarizing plates 60 and 50 are disposed on the front and back sides, respectively, relative to a liquid crystal panel 30. Both the first and second absorptive polarizing plates 60 and 50 are polarizing plates which absorb a specific polarization component and transmit therethrough a polarization component perpendicular to the specific polarization component.
The display 210 as above controls a signal voltage to be applied to the liquid crystal panel 30 and also provides control over turning on or off the light source 10, whereby an image based on an externally provided image signal can be displayed and background light incident from the back side can be transmitted to the front side, as described in Patent Document 1. Thus, the viewer on the front side of the display 210 can see not only an image displayed on the liquid crystal panel 30 illuminated by backlight but also a background by virtue of background light transmitted to the front side when the light source 10 is off.